S B 

615 
W3W3 



Bulletin No. 18. 

U. S. DEPARTMENT OF AGRICULTURE. 

DIVISION OF BOTANY. 



THE WATER HYACINTH, 



AND ITS RELATION TO NAVIGATION IN FLORIDA. 



BY 



HERBERT J. WEBBER. 



^s^X^ 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 
1897. 




Book < W J W $ 



Bulletin 18, Division of Botany, U. S. Dept. of Agriculture 




Bulletin No. 18. 



U. S. DEPARTMENT OF AGRICULTURE. 



DIVISION OF KOTANY. 



THE ¥ATEE HYACINTH, 



AND ITS RELATION TO NAVIGATION IN FLORIDA. 



BY 



HERBERT J. WEBBER. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE. 



1897. 



SB 6/6-" 



MAR 31 l%d 

d. of a 






LETTER OF TRANSMITTAL. 



IT. S. Department of Agriculture, 

Division of Botany, 
Washington, I). C, April 5, 1897. 

Sir: For several years past an aquatic plant known as the water 
hyacinth has been developing to such an enormous extent in the St. 
Johns Eiver, Florida, as to cause serious apprehension in that region 
regarding its possible obstruction to navigation. About two years ago 
the War Department was asked to investigate the matter, and did so. 
In the last session of the Fifty-fourth Congress bills were presented 
proposing an appropriation for fully investigating and for removing the 
obstruction, and one of these bills has again been presented to the 
Fifty-fifth Congress. In answer to urgent requests for exact information 
on the subject, the Department of Agriculture, on January 25, 1897, 
directed one of its agents, Mr. Herbert J. Webber, an assistant in the 
Division of Vegetable Physiology and Pathology, to visit the region 
and prepare a report covering the following points: (1) Historical notes 
regarding the plant, including its habitat, manner of growth, propaga- 
tion, and anatomical and physiological characters; (2) an account of its 
introduction and spread in Florida; (3) the present distribution of the 
plant in the State and its effect on navigation and commerce; and (4) 
possibilities of exterminating it. 

I have the honor to submit Mr. Webber's report herewith, for publi- 
cation as Bulletin No. 18 of the Division of Botany. 
Bespectfully, 

Frederick V. Coville, 

Botanist. 
Hon. James Wilson, 

Secretary of Agriculture. 



CONTENTS. 



Page. 

General notes 7 

Methods of propagation 11 

Introduction and spread of the water hyacinth in Florida 11 

Present distribution in Florida 12 

Damage caused by the water hyacinth 13 

Effect on navigation 13 

Effect on the timber industry 14 

Effect on the fishing industry 15 

Effect on bridges 15 

Effect on health 15 

Possibilities of exterminating the plant 16 

Methods of keeping the pest in control 16 

Mechanical devices 16 

Placing destructive substances in the water 18 

Freezes 18 

Utilization of the water hyacinth as a means of reducing it 19 

Probable effect of diseases in controlling the water hyacinth, St. Jobns 

River, Florida 19 

5 



ILLUSTRATIONS. 



Page. 
Pl. I. Block of water hyacinth at the Palatka Bridge, St. Johns River, 

Florida Frontispiece 

Fig. 1. Water hyacinth 8 

2. Creek covered with water hyacinth 9 

3. Floating masses of water hyacinth 10 

4. Booms for collecting drifting plants 17 

6 



THE WATER HYACINTH AND ITS RELATION TO 
NAVIGATION IN FLORIDA. 



GENERAL NOTES. 

The water hyacinth 1 is a Dative of tropical South America. It has 
clusters of light- blue or violet flowers and blooms freely, and this has 
led to its being widely cultivated in Europe and America. In tropical 
and subtropical America, according to Schouland, 2 it is a common and 
widely distributed weed. The plant is aquatic and commonly floats on 
the surface of the water, without attachment to the soil. If the water 
is shallow, however, the roots may grow into the soft mud and become 
firmly attached. In many places on the banks of the St. Johns River 
the plants may be found growing on the marshy, muddy banks, where 
the roots have a firm attachment to the soil. If the plants are to suc- 
ceed, however, the soil must be thoroughly saturated with water and 
of a loose texture. Even under such conditions they are evidently 
not entirely suited, as they do not grow as large as when floating. If 
the soil becomes comparatively dry, the plants die. 

The leaves of the water hyacinth form a rosette from 1 to 2 feet high. 
This remains above water as the plant floats. The basal portions of 
the leaf stalks of young plants are strongly swollen (fig. 1). As the 
plant becomes older these swellings gradually disappear and the 
petiole lengthens and becomes of nearly equal thickness throughout, 
or gradually tapers from the base to the leaf blade.^ The swellings on 
the petioles of the young leaves act as air reservoirs. In this way they 
insure the stability of the young plant, keeping it from sinking and 
preventing it from being overturned by wind or waves. Old plants 
become so thoroughly entangled that they can be torn apart only with 
considerable difficulty and are in no danger of being overturned. Their 
long petioles are provided with large air chambers, which probably 
contain more air than the short, swollen leaf stems of the young plant. 
The roots form a dense, bushy mass, in many cases reaching a length 
of over 2 feet. 



'Technically known as Piaropus crassipes (Mart.) Britton ; known also in scientific 
publications as Eichhornia speciosa Kunth, and Eichhornia crassipes (Mart.) Solms. — 
F. V. C. 

2 Schonland, S., Pontederiaceae, in Engler and Prantl, die Natiirlichen Pflanzenfa- 
milien, Theil II, Abt. 4, p. 73. 1888. 

'Compare Goebel, Pflanzenbiologische Schildernngen, Theil II, S. 254. 1893. 

7 



8 

The water hyacinth is mostly limited in its growth to sluggish fresh- 
water streams, bayous, lakes, ponds, etc. The character of the water 
appears to have much to do with its growth. In the St. Johns River 
and its tributaries, where the plant has spread so rapidly, the water is 
yellowish or brownish, probably owing to the presence of considerable 
humic acid and organic matter. In clear lakes, where tbe water is 
fairly pure, and in Silver Springs Run, where the water is clear and 
hard, the water hyacinth forms only small, stunted plants. In Blue 
Springs, in which sulphur is sufficiently abundant to be plainly per- 




FlG. 1.— Water hyacinth. 

ceptible to the taste and smell, the plant is said to be unable to sur- 
vive. It can endure only a small percentage of salt and is killed when 
it iioats down into the sea water. In the lower portions of the St. 
Johns River (below Mandarin) the water is evidently too brackish for 
the successful growth of the plant, as it here becomes less abundant, 
notwithstanding the fact that floating masses from the upper portion 
of the river are continually carried down by the current. 

In Florida the plants are generally found lining the shores of tbe 
lakes and rivers in immense numbers. In Monroe, Dexter, George, 



9 

and other lakes, practically the entire shores are lined with a solid 
mass from 50 to several hundred feet wide. Small coves protected 
from the wind are usually entirely covered. The same conditions pre- 
vail all along the St. Johns River from Lake Harney to Green Cove 
Springs. The margins are lined on each side by a broad belt of plants, 
and all coves, bayous, marshes, and small tributary creeks are entirely 
covered (fig. 2). The main channel of the river remains clear unless 
masses of the plants become so packed together as to produce a block. 
In most places, as described above, the hyacinth grows to some extent 
on the wet, muddy shores of the rivers and lakes, all stages of connec- 
tion with the soil occurring as the water becomes deeper. In the course 
of growth and propagation the stolons become so entangled that 1 he 




Fia. 2. — Creek covered with water hyacinth. 

plants whose roots penetrate the soil serve to moor large floating masses 
to the shore. Occasionally the wind or current tears masses of the 
plants loose and these drift with the current or are blown here and 
there by the wind. The quantity of hyacinths present at any point on 
the shore varies greatly from week to week, as the wind largely deter 
mines their position. This is particularly true in large lakes. A steady 
west wind will in a few hours loosen and start great masses of the 
plant from the west shore of a stream toward the east; a strong south 
wind will start large masses downstream; while a strong north wind, 
possibly aided by the tide, 1 will start masses up-stream. It is this 
habit of shifting, principally, that causes the obstruction of navigation. 



1 The tide is noticeable as far up the river as Lake George. 



10 

Iii the sharp turns of the narrow portions of the river the plants are 
caught and form blocks which sometimes extend for several miles. At 
one time during the summer of 1890 a strong north wind drove the 
plants from Lake George up the river and formed a solid mass entirely 
covering the river for nearly 25 miles. At the same time, it is said, 
the south end of Lake George was covered with an unbroken mass of 
plants for nearly a mile from the shore. 

The current carries large masses down the stream and out to sea 
(fig. 3). Tides and winds carry the plants up-stream to some extenl. 
but the general tendency is downstream. The current in the St. Johns 
Eiver is sluggish, being only about a mile and a half per hour, yet its 
effect in carrying the plants out can readily be seen by the blocks formed 
against the railroad bridges, which obstruct the passage of the plant. 
This is particularly the case at Palatka, where there are almost invari- 
ably large accumulations. The bridges across the St. Johns, with the 
exception of that at Jacksonville, are pile bridges, which offer consider- 




Fig. 3. — Floating massrs of water hyacinth. 



able obstruetion to the floating plants (PI. I). In several instances the 
bridges are strengthened by stringers, which run from pile to pile just 
at or below the surface of the water, making the obstruction much more 
effectual. In such cases the span of the drawbridge (To to 00 feet) is 
the only outlet for the plants. The bridges as at present constructed 
retard the passage of the plants out to the sea, and are thus unquestion- 
ably a great hindrance to the clearing of the channel. Wide-span 
bridges offer but little obstruction, and should be required in all permits 
granted for bridges over infested streams. 

In streams with deep, swift currents it is not probable that the weed 
will ever seriously interfere with navigation. In the Ocklawaha Rivei 
the current is much stronger than in the St. Johns, being, in the upper 
part of the river, near Silver Springs Run, about 3£ miles per hour, and 
in the lower part, near its mouth, about 2£ miles per hour. AVhile this 
stream is very tortuous, the weed has not accumulated to any serious 
extent along the shores and no blocks have occurred. The swift current 
tears the plants loose from the shore as soon as they extend into the 



11 

river beyond the projecting roots of the trees, and hurries them down 
the stream and eventually into the St. Johns River. The boatmen and 
lumbermen who navigate the Ocklawaha do not think the weed will 
ever form any obstruction to navigation here, and this opinion would 
seem to be well founded. 

METHODS OF PROPAGATION. 

The water hyacinth is normally propagated by seeds and by stolons. 
The writer has been unable to ascertain positively whether the plant 
in Florida forms seeds, but the evidence obtained strongly indicates 
that it does. 1 The flowering is very profuse, and there seems to be no 
reason why seeds should not mature. The propagation by stolons is 
very rapid and effectual. The stolons branch out from the old stem, 
extend from 4 to 8 inches from the parent plant, and form on their ends 
a little rosette of leaves (tig. 1). Roots spring from the node where the 
rosette is formed, and the young plant soon becomes self-supporting. 
Old plants will usually be found to have formed several (three to five or 
more) stolons, which branch out in different directions. Several genera- 
tions of plants produced iu this way may frequently be found connected 
by the old stolons, which are usually about one-half an inch in diam- 
eter and are very strong. The writer has several times counted from 
twenty to thirty plants so attached. As the plants usually grow close 
together the newly developed offshoots bind the mass firmly together, 
so that it is difficult to separate the individual plants. 

INTRODUCTION AND SPREAD OF THE WATER HYACINTH IN FLORIDA. 

Nothing accurate has been learned as to when the water hyacinth 
was first cultivated in the State for ornament. It has been many years 
under cultivation in Northern hothouses and has probably been grown 
in Florida for a considerable time. As nearly as can be learned, how- 
ever, it was first introduced into the St. Johns River about 1890, at 
Edgwater, about 4 miles above Palatka. At this place it had been 
grown for some time in a pond, and when it was desired to clear the 
place out the plants were thrown into the river. Here they grew luxu- 
riantly, producing beautiful masses of flowers, which rendered the 



'In a fountain basin in the yard of Dr. R. P. Daniels, of Jacksonville, Fla., the 
water hyacinth was grown for several years. When it was desired to kill it, all 
the material visible was carefully taken out, but the plants came up again. The 
water was then drained off*. and the earth thrown out of the fountain basin and 
allowed to dry for about three months, during which time it was exposed to the 
severe freezes of 1894-95, and then replaced, no living portions of the plant being 
observed in the operation. In a short time, however, numerous minute plants, which 
proved to be young water hyacinths, appeared on the bottom. In this case it is 
thought that the plants must have come from seeds. The writer has also learned of 
another similar case. In this connection it is interesting to recall that Fritz Miiller 
has shown that the seeds of the water hyacinth will not germinate until they have 
been dried out (Kosmos, 1883, VII, Heft 4, pp. 297-300; review in Bot. Centralbl., 
Bd. 16, p. 299). 



12 

river attractive. At this time no one had any idea the plant would 
become a nuisance, and it was carried by settlers up and down and 
introduced at different points to beautify the river in front of settle- 
ments. It was also distributed by boats passing up and down, and 
it soon became abundant up as far as Lake Monroe and down as far 
as tbe increasing brackishness of the water allowed its growth. In 
1894 the water hyacinth had become so abundant that it began to 
attract the attention of steamboatmen and fishermen, although at that 
time the amount was not sufficient to cause trouble. After the severe 
storms of October, 1804, which carried the plants out of the bayous and 
creeks, they were noticed to be very abundant. 

In October, 1894, some plants were carried up the Ocklawaha River, 
the main tributary of the St. Johns, and placed in a pool at Howard's 
Landing, 14 miles down the river from Silver Springs. This became the 
seed bed for the entire lower and navigable portions of the Ocklawaha 
River. The plants multiplied rapidly and were crowded out into the 
river. The current carried them downstream and has spread them 
along the entire lower portion of the river. 

PRESENT DISTRIBUTION IN FLORIDA. 

So far as can be learned, the distribution of the water hyacinth in 
Florida is limited to the St. Johns River and its tributaries and a few 
inland lakes and ponds. It extends down the river in great abundance 
as far as Doctors Lake or Mandarin. Beyond this point it may be 
found in considerable quantity, usually floating down the river, but the 
water is evidently too salty for the healthy growth of the plant. It is 
abundant as far up as Lake Harney and has been introduced in places 
still farther up the river, occurring to some extent, the writer is 
informed, as far as Puzzle Lake. From Lake Harney to Green Cove 
Springs, a distance of over 200 miles, it is very abundant. In the 
Ocklawaha River it lines the shores from the mouth of Silver Springs 
Run to the St. Johns River, a distance of about 100 miles. It has 
spread only a few miles up the Ocklawaha above the entrance of Silver 
Springs Run. There is no navigation above this point, and as the cur- 
rent of the stream is swift it is difficult for the plant to extend in this 
direction. The writer is informed by those who know the river at this 
point that the water hyacinth has now extended about 5 miles above 
Silver Springs Run. Occasional plants may be observed in this stream, 
but the water is evidently not suited lOthem and they remain small and 
do not propagate rapidly. As far as the writer has been able to learn 
by personal observation and inquiry, the large lakes, comprising the 
head waters of the Ocklawaha (Lakes Harris, Dora, Eustis, Griffin, and 
others), remain free from the pest. Deep Creek and Crescent Lake, 
through which the regular line of boats run and on the shores of which 
are extensive and valuable lumber forests, are badly infested. Rice 
Creek, Black Creek, and almost all the numerous small tributaries of 



13 

the St. Jolms, are covered by a solid mass of the plant (fig. 2). As far 
as can be learned, the Wekiva River, which contains large quantities of 
the water lettuce (Pistia stratiotes L.), has become infested with the 
water hyacinth only for a short distance up from its confluence with the 
St. Johns. Certain small lakes at Orlando, Tampa, and Ocala are 
known to be infested, and it is probable that there is a considerable num- 
ber of lakes in the State where it has been introduced. The navigable 
rivers of the State other than the St. Johns, such as the Kissimmee, 
Withlacoochee, Suwanee, and Apalachieola, are as yet apparently Iree 
from the weed. However, it is liable to be introduced into these streams 
at any time for cattle food or because of its showy flowers, and precau- 
tionary measures should be taken to prevent its further spread. Stock- 
men are said to have carried the plant up the St. Johns River by the 
boat load to introduce and spread it as food for their cattle. 1 

DAMAGE CAUSED BY THE WATER HYACINTH. 

EFFECT OX NAVIGATION. 

That the wat' r hyacinth is becoming a serious menace to navigation 
in the St. Johns River is unquestionably true. Small boats with screw 
propellers find it impossible to penetrate a very large mass of the plants, 
as they lack the necessary power, and the plants soon become entangled 
in the screw and prevent it from revolving. Parting the plant with 
boat hooks, etc., is very slow and tedious. Paddle-wheel steamers are- 
able to penetrate the extensive masses of the plants much better, but 
are generally hindered and frequently entirely blocked. When a large 
steamer going at full speed strikes a bank of the hyacinths, it conies 
almost to a standstill. In side wheel steamers the plants collect between 
the wheel and bulkheads, packing in so solidly that it is often almost 
impossible to reverse the engine. This necessitates caution in approach- 
ing the landings. Steamers with low-pressure engines are troubled by 
the clogging of the injection pipes so that sufficient water can not be 
secured for the condensers. In the case of some boats the obstruction 
is occasionally removed by blowing steam through the injection pipe. 
This process, however, is rather dangerous, as the injection pipes and 
condensers are not constructed with a view to having heavy pressure 
applied from within. Floating logs frequently lie concealed in the 
masses of the plants and form a serious danger to navigation. Sev- 
eral boats have already been injured to some extent by striking such 
obstructions. 

In large lakes, like Lake George, and in wide portions of rivers, 
there is some danger of steamers being caught between floating masses 
of the plants, carried out of the channel, and stranded. The City of 
Jacksonville, the largest and most powerful steamer plying on the St. 

'The writer is of the opinion that the State should enact laws making the intro- 
duction of the water hyacinth into rivers and into lakes having outlets a misdemeanor. 



14 

Johns, at one time in the fall of 1806 had great difficulty in avoiding 
this. Small launches, rowboats, sailboats, etc., have in several in- 
stances been caught between masses of the floating plants and have 
found it impossible to get out without aid. In many places it has 
become dangerous to use small boats. 

Similar difficulties have been encountered in northern South Amer- 
ica, the native home of the plant, where it frequently becomes so abun- 
dant in sluggish streams as to be a serious obstacle to navigation. 
Goebel, a German botanist, says that " in many streams in Guiana the 
plant has become a plague to steamers, as it frequently almost entirely 
covers the surface and easily becomes entangled in the ship's screw." ' 

The rapid increase of the water hyacinth in the St. Johns Eiver in 
the short time since it was introduced strongly indicates its still fur- 
ther increase if means are not found to keep it in control. Should it 
become much more abundant, navigation will be entirely stopped — at 
any rate in the upper portion of the river south of Palatka. This 
would mean a serious disaster to a large and important region of the 
State. About eight steamers ply regularly up and down the St. Johns 
and Ocklawalia rivers, carrying freight, mail, and passengers. The 
entire section reached by the St. Johns River steamers is, furthermore, 
greatly benefited by the low freight rates secured owing to water com- 
petition. The rates where competition exists are only about one-half 
or one third those to places of equal distance not having water trans- 
portation. Should the water hyacinth become much more abundant, 
many of the small tugs and launches now doing business on the St. 
Johns Eiver will be unable to run. 

EFFECT ON THE T1MBKR INDUSTRY. 

Bordering the St. Johns River and its tributaries are extensive and 
valuable forests of cypress, pine, and red cedar, which are largely 
sawed by mills located in Palatka and Jacksonville. The logs are cut. 
and rafted down the St. Johns to the mills, much being saved by trans- 
porting them in this way. Over twenty tugs, it is said, are engaged 
in this rafting business. Great difficulty has been experienced by the 
lumbermen in getting their rafts out of the small tributaries, which 
become entirely covered by dense masses of the water hyacinth (fig. 2). 
From Palatka alone there is shipped annually about 55,000,000 feet of 
lumber, representing a value in the raw material of about $110,000. 
The difficulty in rafting caused by the water hyacinth is estimated by 
lumbermen to cause a loss of about one-fourth the value of the logs, 
so that the yearly loss to lumbermen at Palatka from this pest would 
thus be about $27,500. At present twice this amount, or $55,000, 
would probably be a fair estimate of the yearly damage to the lumber 
industry of the entire river. 



l'flanzenbiologische Schilderungen, 2, p. 255. 1893. 



15 

EFFECTS ON THE FISHING INDUSTRY. 

Fishing for sliad and other fresh-water fish has for years been an 
important industry on the St. Johns River. Since the water hyacinth 
has become abundant, however, much difficulty is experienced in operat- 
ing the nets. Occasionally at certain places fishermen are unable for 
days at a time to use their nets, or do so at great risk, as the net may 
be caught between floating masses of the hyacinth and carried away. 
All along the river it is difficult to find clear places on the banks on 
which to laud the nets, and it is usually necessary to spend some time 
in clearing the water hyacinth away in order to provide a suitable 
place. The detritus of dead plants which accumulates on the bottom 
of the river is also some hindrance to fishermen. Previous to the 
introduction of the water hyacinth the bottom of the river in most 
places was sandy and clear of obstruction. Now in many places, the 
writer is informed, the decaying plants have collected in masses several 
feet deep. On the fish, however, the effect of the rapid spread of the 
plant has apparently been beneficial, as they are more abundant now 
than ever before. Fishermen think this is due to the protection which 
the masses of vegetation afford to the young fish. 

Should the hyacinth spread in the next four years as rapidly as it 
has in the past four, fishing with nets will probably have to be aban- 
doned. The obstruction has already become serious in some places. 
One fisherman, having about 30 men employed constantly, informs the 
writer that lie has been damaged to the extent of over $1,000 this 
year by the loss of time and nets caused by the water hyacinth. 
Probably 500 men along tue St. Johns depend upon this industry for 
their sustenance. 

EFFECT ON BRIDGES. 

In floods the banking up of the masses of water hyacinth, and the 
resistance offered thereby to the passage of water, is liable to prove dis- 
astrous to bridges. The railroad bridge across Rice Creek was consid- 
erably injured duriug the flood of 1894, some 65 feet of the trestle being 
destroyed. The force of the water in this was doubtless greatly 
increased by the presence of the hyacinth. Some trouble is also expe- 
rienced by the washing produced by undercurrents caused by the plants 
banking up against the bridges. At the Buffalo Bluff bridge men 
have been employed to push the plants through to prevent a block. 

EFFECT ON HEALTH. 

There is much complaint of the unwholesome conditions produced 
by the water hyacinth, particularly in the towns of Palatka and San- 
ford. While the plant itself is not directly injurious to health, the 
accumulation of large masses of decaying vegetable matter on the 
banks and in lagoons probably affects the general healthfulness of a 
region. When the wind blows steadily iu one direction for some time, 



16 

it piles many of the plants upou the shore, where they are left to rot. 
Again, the blocking of small streams may interfere with drainage and 
the passage of sewage waters, and thus render conditions uuhealthful. 

POSSIBILITIES OF EXTERMINATING 'J HE PLANT. 

As explained above, the water hyacinth lines the shores of the St. 
Johns River from Puzzle Lake to Mandarin, being very abundant from 
Lake Harney to Green Cove Springs, a distance of considerably over 
200 miles. Throughout this entire distance the shores of the river and 
the numerous large lake expansions are lined with a border of the plant 
from 25 to 200 feet wide. The coves, bayous, marshes, and creeks, with 
few exceptions, are covered by a continuous dense mat of the plants. 
No reliable data can be secured as to the actual extent of the coast line, 
but in the St. Johns alone, not including the Ocklawaha, it would 
probably exceed 1,000 miles. The Ocklawaha River, which is*badly 
infested for over 100 miles of its length, would greatly increase the 
coast line, which must be considered if extirpation is proposed. 

Extirpation, if successful, means the destruction of every plant and 
every seed or rootstock which may give rise to a new plant. It would 
be comparatively easy to destroy the great bulk of the plants, but 
exceedingly difficult to eradicate the fragments here and there trodden 
into the mud or hidden under roots. The entire shore line of the St. 
Johns and all its tributaries would have to be carefully searched several 
seasons in succession. Eradication may be possible, but the writer 
greatly doubts its feasibility. Considering the immense extent of ter- 
ritory and the inaccessibility of a large part of it, it is not probable 
that every plant could be destroyed, and were a few left they would 
in the course of a few years reinfest the entire territory. If the plant 
forms seeds in Florida, which is thought to be the case, the difficulty 
would be greatly increased, as some of the seeds might retain their 
vitality for a number of years. On the whole, the writer has been 
forced to the conclusion that eradication is impracticable. He finds, 
furthermore, that those who have given the matter candid consideration 
mostly agree in this opinion. The evil, however, is certainly so serious 
that means should be devised, if possible, to keep it in check. This, 
it is believed, can be accomplished at fairly reasonable expense. 

METHODS OF KEEPING THE PEST IN CONTROL. 

The water hyacinth is easily killed in many ways, but only those 
methods which are thought to be the most practicable can be discussed 
here. 

MECHANICAL DEVICES. 

Probably the most feasible device for killing the plant is that sug- 
gested by Mr. Sackett, Assistant Engineer of the War Department. 
He recommends the "construction of a light-draft stern wheel steamer, 
having a double bow or outrigger, which being forced into a mass of 



17 

plants would cause them to gather toward the middle of the boat, 
where an inclined carrier would pick them up and deposit them in front 
of rollers driven by machinery, which would force the water from them, 
thus greatly reducing their bulk. The crushed material could be deliv- 
ered to barges alongside, to be deposited where no injury could again 
result, or a cremator could be arranged on a barge alongside of the 
boat, and so save additional handling." 1 It would seem to the writer 
perfectly feasible to construct the crushers suggested by Mr. Sackett 




Fie. 4. — Booms for collecting drifting plants. 

strong enough so that the plants would be destroyed, in which case the 
fragments could simply be dumped into the river. In an apparatus of 
this kind the danger to the machinery from hidden trash and logs must 
be considered. By having a lever with which the carrier could be 
quickly stopped a man constantly on guard could probably prevent 
serious accident to the machinery. 



'Senate Report No. 1395, Fifty-fourth Congress, second session, p. 5, 1897. 
16013— Xo. 18 2 



18 

A boat constructed like the above, but with carriers to deposit the 
plants on the shore instead of crushing them, could be used to advan- 
tage in many places. If worked in connection with booms constructed 
at points along the river to collect the plants, it is possible that this 
plan would prove more satisfactory than the above. Floating log 
booms could be constructed at favorable points, as shown in fig. 4, 
to collect the plants. The dredge working near the shore could then 
easily throw the plants out upon dry land. When all the plants which 
had accumulated at one point were destroyed, the dredge could pro- 
ceed to another station. By destroying the plants thus collected at 
regular intervals along the river, which could be done at comparatively 
small expeuse, it is thought the river could be kept open to navigation. 
In case either method were followed, log booms should be placed across 
the entrances to bayous, creeks, etc., to confine the large masses of 
plants as far as possible and prevent their rapid reproduction. It has 
been demonstrated that this can be easily accomplished. The carrier 
device to deposit the plants on the shore would be particularly effective 
in canals. In regard to mechanical devices, however, it may be said 
that they are all simply temporary expedients. 

PLACING DESTRUCTIVE SUBSTANCES IN THE WATER. 

Pouring gasoline on the water and igniting it has been suggested as 
a means of killing the water hyacinth, but on account of the great 
expense this would entail and the danger from fire it is not believed 
to be practicable. Destruction by salting or poisoning the water or 
covering the surface with kerosene or crude petroleum has also been 
suggested, but it is believed that these methods would prove of little 
value. 

FREEZES. 

Such freezes as are likely to occur in Florida can not be expected to 
kill the water hyacinth. The writer carefully observed the effects of 
the very severe freezes of 1894 and 1895, and found that while the plants 
were severely injured few were entirely killed. The first freeze, that 
of December 29, 1894, killed the tops down to the surface of the water. 
These soon dried up, and the plant, relieved of the heavy top, arose in 
the water so that a considerable portion of the usually submerged base 
was exposed. The second freeze, February 9, 1895, killed this exposed 
portion, which normally would be covered, and yet the plants were not 
destroyed. The majority of them sprouted from the small remaining 
basal portion Avhich was not injured. In most locatious the cold 
weather of this winter (January 27,28, 1897, 21° to 25° F.) killed the 
tops of the plants, but has only slightly checked their spread. 



19 

UTILIZATION OF THE WATER HYACINTH AS A MEAN'S OF REDUCING IT. 

As mentioned above, the water hyacinth is a good food for cattle and 
hogs, and hundreds of these animals may be seen along the shores of 
the St. Johns in the winter grazing on the weed. The plant has been 
used to some extent for a fertilizer, being put on both when rotted and 
while green. With some garden crops, such as potatoes and cabbage, 
it is said to have given excellent results. The fertilizing properties of 
the plant must, however, be comparatively small, as a large percentage 
of it is air and water. However, the various uses to which the plant 
may be put can not be expected to involve its destruction to a sufficient 
extent to aid materially in keeping it under control. 

PROBABLE EFFECT OF DISEASES IN CONTROLLING THE WATER HYACINTH. 

From what has been said, it appears that the eradication of the water 
hyacinth by mechanical means is practically impossible, and that the 
use of dredges and other mechanical devices will simply result in keep- 
ing the plant in control at continuous expense. There is, however, 
another means of combating pests of this nature, namely, the intro- 
duction and spread of their natural enemies, which in some instances 
has proved thoroughly effective. The water weed, or water pest (Phi- 
lotria canadensis (Michx.) Brittou), which when first introduced into 
Europe caused very serious trouble in canals and rivers and then grad- 
ually disappeared, is probably a case of this nature. The female plants 
of the water weed were introduced into Ireland in 1830, into Great 
Britain in 1841, and later into many rivers and canals in middle, 
southern, and northern Europe. The weed multiplied rapidly and soon 
became very troublesome to navigation and fisheries in many canals 
and streams. After a number of years it became less abundant, repro- 
ducing less rapidly, and gradually decreasing in most places until it 
no longer causes serious trouble. 1 Many authorities attribute this 
decreased reproduction to the effect of natural enemies, which have 
gradually multiplied until they keep the pest under control. The 
water weed roots in the muddy bottoms of rivers and canals, and some 
authorities attribute the decreased numbers of the plant to the exhaus- 
tion in the soil of the specific nutriment on which the plant feeds. The 
water hyacinth, however, is a floating plant, having commonly no con- 
nection with the soil, and therefore could not be affected in this way. 

The introduction of the lime tree (Citrus limetta) on some of the 
Florida keys furnishes an illustration of a similar nature. If the lime 
is introduced entirely free from its natural enemies it grows rapidly and 
thrives without culture. If, however, a single enemy of the lime, for 
instance, the purple scale insect (Mytilaspis citricola), be introduced, 
the trees will be killed to the ground, if not killed out entirely. If, 
however, when the purple scale is introduced, its fungous and insect 



•Ascherson and Giirke, Hydvocharitaceae, in Engler and Prantl, Die Naturlichen 
Pflauzeiifaimlieii, Theil II, Abt. I, p. 251. 1889. 



20 

enemies, which on the mainland of Florida keep the pest in control, 
are also introduced, the scale will probably not be allowed to increase 
rapidly enough to seriously injure the lime. 1 

The writer has made a careful search in Florida for diseases which 
may prove of importance in combating the water hyacinth and has 
discovered one leaf-spot malady which is widely distributed and unques- 
tionably damages the plant considerably. This disease is caused by a 
parasitic fungus which attacks the leaves in spots, forming concentric 
circles, and ultimately kills the entire leaf. It is highly important, in 
the writer's opinion, that a careful search should be made in the native 
home of the plant for additional diseases which may be introduced 
here to aid in keeping the pest under control. Although it is by no 
means certain that any exceedingly virulent diseases would be found, 
yet many minor maladies would doubtless be discovered which would 
aid in controlling the weed. The introduction of the natural enemies 
of the plant, together with the remodeling of the bridges in order to 
allow the river current to carry as much of the material out to sea as 
possible, would probably keep the pest down so that it would not 
seriously obstruct navigation. This would necessitate but small initial 
expense and, if successful, would permanently solve the question. 

'Throughout the principal regions of Florida where the lime and other citrous 
fruits are grown, the purple scale is attacked hy a very virulent fungous disease. 
This is caused by Ophionectria coccicola E. and E., which has been shown by experi- 
ment to be very effective in keeping this pest under control. Under ordinary 
circumstances this disease, aided by the ladybird beetle and other parasitic enemies, 
so thoroughly destroys the purple scale that it causes no serious damage. 






